Interconnect structure of semiconductor device and method of forming same

Abstract

A device includes a substrate, a dielectric layer over the substrate, and a conductive interconnect in the dielectric layer. The conductive interconnect includes a barrier/adhesion layer and a conductive layer over the barrier/adhesion layer. The barrier/adhesion layer includes a material having a chemical formula MX n , with M being a transition metal element, X being a chalcogen element, and n being between 0.5 and 2.

What is claimed is: 
     
       1. A method comprising:
 forming a dielectric layer over a substrate; 
 patterning the dielectric layer to form an opening in the dielectric layer; 
 forming a barrier/adhesion layer along a bottom and sidewalls of the opening, a material of the barrier/adhesion layer having a chemical formula MX n , with M being a transition metal element, X being a chalcogen element, and n being between 0.5 and 2, wherein forming the barrier/adhesion layer comprises:
 depositing a layer of the transition metal element along the bottom and the sidewalls of the opening; and 
 after depositing the layer of the transition metal element, performing a chalcogen treatment on the layer of the transition metal element; and 
 
 depositing a conductive layer over the barrier/adhesion layer in the opening. 
 
     
     
       2. The method of  claim 1 , wherein depositing the layer of the transition metal element comprises performing a physical vapor deposition (PVD) process. 
     
     
       3. The method of  claim 1 , wherein performing the chalcogen treatment comprises performing a plasma enhanced chemical deposition (PECVD) process using a precursor comprising the chalcogen element. 
     
     
       4. The method of  claim 1 , wherein depositing the conductive layer comprises depositing a seed layer over the barrier/adhesion layer in the opening, the seed layer filling the opening. 
     
     
       5. The method of  claim 1 , wherein depositing the conductive layer comprises:
 depositing a seed layer over the barrier/adhesion layer in the opening; and 
 depositing a conductive fill material over the seed layer in the opening, the conductive fill material filling the opening. 
 
     
     
       6. The method of  claim 1 , wherein the barrier/adhesion layer comprises a plurality of sub-layers. 
     
     
       7. A method comprising:
 forming a first dielectric layer over a substrate, the first dielectric layer having a recess; 
 forming a conductive via in the recess in the first dielectric layer, forming the conductive via comprising:
 forming a first barrier/adhesion layer comprising a first material, the first material having a chemical formula MX n , with M being a transition metal element, X being a chalcogen element, and n being between 0.5 and 2; and 
 forming a first conductive layer over the first barrier/adhesion layer; 
 
 forming a second dielectric layer over the first dielectric layer and the conductive via; and 
 forming a conductive line in the second dielectric layer, forming the conductive line comprising:
 forming a second barrier/adhesion layer comprising the first material; and 
 forming a second conductive layer over the second barrier/adhesion layer. 
 
 
     
     
       8. The method of  claim 7 , wherein forming the first barrier/adhesion layer comprises:
 depositing a layer of the transition metal element along a bottom and sidewalls of the recess; and 
 after depositing the layer of the transition metal element, performing a chalcogen treatment on the layer of the transition metal element. 
 
     
     
       9. The method of  claim 7 , wherein forming the first barrier/adhesion layer comprises:
 depositing the first barrier/adhesion layer using a deposition process, the deposition process performed using a metal-containing precursor and a chalcogen-containing precursor. 
 
     
     
       10. The method of  claim 7 , wherein the first barrier/adhesion layer has a layered structure. 
     
     
       11. The method of  claim 7 , wherein forming the conductive via further comprises:
 forming a first seed layer over the first barrier/adhesion layer, the first seed layer being an uppermost layer of the conductive via. 
 
     
     
       12. The method of  claim 7 , wherein forming the first conductive layer comprises:
 forming a first seed layer over the first barrier/adhesion layer; and 
 forming a first conductive fill layer over the first seed layer, a top surface of the first conductive fill layer being level with a top surface of the first dielectric layer. 
 
     
     
       13. The method of  claim 7 , wherein forming the second conductive layer comprises:
 forming a second seed layer over the second barrier/adhesion layer, the second seed layer being an uppermost layer of the conductive line. 
 
     
     
       14. The method of  claim 7 , wherein forming the second conductive layer comprises:
 forming a second seed layer over the second barrier/adhesion layer; and 
 forming a second conductive fill layer over the second seed layer, a top surface of the second conductive fill layer being level with a top surface of the second dielectric layer. 
 
     
     
       15. The method of  claim 7 , wherein the second barrier/adhesion layer is in physical contact with the first conductive layer. 
     
     
       16. A method comprising:
 forming a first dielectric layer over a substrate; 
 patterning the first dielectric layer to form a via opening in the first dielectric layer; 
 depositing a barrier/adhesion layer along a bottom and sidewalls of the via opening using a first deposition process, the first deposition process using a metal-containing precursor and a chalcogen-containing precursor, a material of the barrier/adhesion layer having a chemical formula MX n , with M being a transition metal element, X being a chalcogen element, and n being between 0.5 and 2; 
 depositing a conductive layer over the barrier/adhesion layer in the via opening; 
 depositing a second dielectric layer over the first dielectric layer and the conductive layer; and 
 forming a conductive line in the second dielectric layer, wherein the conductive line contacts the conductive layer. 
 
     
     
       17. The method of  claim 16 , wherein the barrier/adhesion layer has a plurality of sub-layers, wherein each of the sub-layers has a thickness in a range of 0.5 nm and 1 nm. 
     
     
       18. The method of  claim 16 , wherein the metal-containing precursor comprises pentakis (dimethylamino) tantalum (V), tantalum ethoxide, or tantalum chloride, wherein the chalcogen-containing precursor comprises dimethyl disulfide or H 2 S. 
     
     
       19. The method of  claim 16 , wherein the barrier/adhesion layer has a plurality of wavy sub-layers. 
     
     
       20. The method of  claim 1 , wherein the conductive layer is part of a conductive via, further comprising:
 depositing another dielectric layer over the dielectric layer and the conductive via; and 
 forming a conductive line in the another dielectric layer, wherein the conductive line contacts the conductive via.